Hynd Bio 270 Lecture Exam 2

Tropomyosin (thin filament) (2)

-threadlike component that covers binding sites when muscle is relaxed

3 filaments in smooth muscle

1) thick myosin 2) thin actin 3) intermediate size filament (do not contract, supports cell shape)

humans can hear sounds between

20-20,000 Hz

Aphasia: language disorders caused by damage to specific cortical areas

-Broca's aphasia: unable to form words but can understand written and spoken language -Wernickes aphasia: unable to understand words seen/heard but ability to speak words=unaffected

Skeletal muscle vs cardiac muscle excitation-contraction coupling

-Skeletal= increasing frequency -> tetany -Cardiac= no 2nd AP or contraction since stimuli arrive during refractory

radial muscle of iris

-active in dim light -stretches (dilates) pupil -sympathetic NS

cones= 3 protein sensitive specific wavelengths

-blue (425-475 nm) -green (525 nm) -red (560 nm)

roles of efferent division of PNS

-carries motor commands from CNS to PNS muscles and glands -directed at maintaining homeostasis

cones

-cone opsin photoreceptor -respond to various wavelengths (colors) -low sensitivity to light=works best in bright light -high visual acuity -more numerous in fovea

anterior cavity of eye

-filled with aqueous humor -carries nutrients to cornea and lens (no blood supply) -continuously renewed and in motion

Smaller receptive fields yield

-greater acuity or discriminative ability (more sensitive areas of body have smaller receptive fields)

valve function

-in order for a valve to be open the blood pressure behind the valve has to be GREATER than the pressure in front of the valve -valves open/close solely on pressure gradients

types of andrenergic receptors: beta 2 receptors

-inhibitory response for arterioles and lung airways, relaxes and dilates smooth muscle in response to fight or flight to increase blood flow

neuromuscular junction sites are in the middle of cylindrical muscle fiber so

-local current flow (EPP) spreads both directions -reduces potential to threshold in adjacent areas -AP spreads both directions AWAY from motor end plate

types of cholinergic receptors

-nicotinic= bind on postganglionic cell in both the sympathetic and parasympathetic NS -muscarinic=bind Ach from parasympathetic postganglionic neurons on effector organ cell membranes

3 layers of excitable tissue in the retina

-photoreceptors -bipolar cells -ganglion cells

sympathetic NS

-preganglionic nerve (cholinergic fibers release Ach) and postganglionic nerve (adrengeric fibers release NE and/or Epi)

AV block

electrical disconnect between atria and ventricles in conduction of electricity, 3 degrees of severity, 2 pacemakers=no patterns btwn top and bottom of heart

pitch

frequency of sound waves

reflex arc

innate response to a stimulus

12 lead EKG

look at slightly different angles of heart and electrical current spread to pinpoint abnormality to precise region

Interneurons

Only in the CNS, integrate info and form efferent response, used in higher mental functions

EKG's can diagnose

abonormalities

the binding groove is or is not exposed all the time

IS NOT

Gilal cells

cells in the nervous system that support, nourish, and protect neurons

sound is measured in

decibels

timbre (quality)

depends on overtones

Botox

Blocks release of ACh at the neuromuscular junction which aims to paralyze muscles to prevent muscle cell from contracting (wrinkles)

Blood-brain barrier

Blood vessels (capillaries) that selectively let certain substances enter the brain tissue and keep other substances out

lateral sacs store

Ca2+

Iris

Controls the amount of light entering the eye thru the pupil, 2 sets of smooth muscle (circular and radial)

Afferent neurons

Inform CNS about conditions in both the external and internal environment

2 types of smooth muscle

single unit and multi unit

The left ventricle is

stronger and thicker than the right b/c it has to pump blood to all body tissues so it is more O2 rich and higher pressure+ resistance

Receptors

structures at peripheral endings of afferent neurons that detect different stimuli

Divisions of the ANS

sympathetic and parasympathetic

the more rounded the lens

the greater refractive power

Muscles are the largest group of

tissues

heart sounds: S2

"dub": aortic and pulmonary (semilunar) valves closing at onset of diastole

heart sounds: S1

"lub": mitral and tricupsid (AV) valves closing at beginning of systole

differences between AP of cardiac contractile cells compared to authorhythmic cells

- AP delivered to contractile cells initiated by SA node -has resting potential (-90mV) -prolonged depolarization accompanied by prolonged contraction ensures adequate ejection time -3 types of K+ channels

Myosin (thick filament)

-2 identical subunits (tails wrap around each other and heads project out) -heads form linkage w/ actin of thin filament to form a crossbridge -contain actin binding sites and myosin ATPase sites where ATP binds and liberates energy for muscle contration

external auditory canal

-2.5 cm long -runs from auricle to tympanic membrane (eardrum) -lines with hairs and sweat glands to make ear wax

Muscle metabolism

-4 steps in excitation-contraction-relaxation process require energy 1) ATP is hyrdolyized & split by myosin ATPase which provides energy for powerstroke 2) binding of fresh ATP detaches actin/myosin cross bridges 3) Active transport of Ca2+ back into SR during relaxation 4) Active transport of Na+ and K+ following muscle cell AP

switching off the signal

-ACh signal must be turned off and cleared when the motor neuron stops firing in order for new movement -Acetylcholinesterase inactivates Ach in the neuromuscular junction by breaking it down into parts and clears out the synapse

intercalated discs

-Between to cardiac muscle cells, helps with communication between cells 1) desmosomes: anchor 2 non touching cells 2) gap junctions: small connecting tunnels for electric current to spread impulses cell to cell, and allow for muscle contraction as a single unit

Clinical correlation= morphine

-Bind to opioid receptors in brain and spinal cord since it doesn't readily cross the BBB -diacetylmorphine is more fat soluble and crosses the BBB much quicker and the converts to morphine

Parasympathetic NS

-Both preganglionic and postganglionic nerves (cholinergic fibers release Ach)

calcium and the sarcoplasmic reticulum (SR)

-excitation contraction coupling=series of events linking AP to muscle contraction -AP travels down T-tubules -depolarization of T-tubules open Ca2+ channels in lateral sacs of SR and is released into the cytosol where it binds to troponin

types of andrenergic receptors: beta 1 receptors

-excitatory response, found in heart muscle, increases heart rate and force at which heart is contracting= raise in blood pressure

ventral root

-exit for motor fibers

autonomic nerve pathway

-extends from CNS to effector organ -2 neurotransmitters that control effector organ response (Ach & Epi/NE)

farsightedness (hyperopia)

-eyeball is to short or lens is too weak -focal point falls behind retina -treated with convex lens

nearsightnedness (myopia)

-eyeball is too long/strong for lens and the focal point falls in front of the retina -treated with concave lens to diverge light rays

clinical correlation: mitral valve prolapse

-failure of mitral valve= congestive heart failure -backup of blood, causes unknown -symptoms: fatigue, chest pain, SOB, lightheaded -treatments: repair valve, replace valve (metal or pig)

posterior cavity of eye

-filled with jelly like vitreous humor -provide eye with spherical shape by creating pressure -never renewed

ejection fraction

-fraction of blood pumped from ventricle with each beat -at rest 55-65% -increases w/ 2 controls

troponin (thin filament) (3)

-glue that holds tropomyosin in binding groove when muscle is relaxed -binds to tropomyosin, actin, an Ca2+ -when not bound to Ca2+, troponin positions tropomyosin in actins myosin cross bridge binding site -upon binding of Ca2+, it loses its grip on tropomyosin, causing it to slip off and expose binding sites

Electrical response of photoreceptors

-in the dark, rods and cones are depolarized so Na+ channels are constantly open -activation of photopigment by light causes Na+ channels to close= hyperpolarization=reduction of inhibitory neurotransmitter release onto bipolar cells

Twitch summation

-increased force of contraction by increasing AP frequency -2nd AP occurs before complete relaxation from 1st contraction ("piggybacks" off first twitch) -results from sustained elevation of cytosolic Ca2+ -tetany occurs if muscle fiber is stimulated so rapidly that it does not relax between stimuli (100 % max contraction when increase frequency of AP)

Brain stem

-junction between brain and spinal cord -oldest region of brain (has remained unchanged for longest) -consists of medulla, pons, and midbrain -medulla=continuous w/ spinal cord, contains clusters of cells known as "centers" that control vegetative processes (breathing, swallowing, etc.)

neuromuscular junction

-junction between the somatic motor neuron and a single muscle cell (fiber) -cleft is too large for electrical transmission so the signal must go from (electrical-chemical-electrical)

AP and muscle twitch relationship

-latent time= delay between stimulation and onset of contraction -contraction time= time btwn onset of contraction until max tension -contraction time < relaxation time

the refractive ability of the ______ can be adjusted by changing the curvature for near/far vision

-lens (biconvex disc) -the more curved the lens, the more able to bend light

Refractory period of contractile cells

-long refractory period (250 m/sec) prevents temporal summation and tetany -important b/c it allows complete contraction and relaxation of a muscle cell before another AP and contraction response -if heart gets locked into max contracted state it is not pumping anything whichs = HR of 0

Stimuli exist in various

-modalities (temp, sound, pressure) AND -sub-modalities: (warm&cold, loud&quiet, etc.)

cerebral cortex: parietal lobe (contains somatosensory cortex)

-more sensitive areas of the body have more areas of the brain devoted to this spot -associated with somesthetic sensations -receives info from contralateral side of body

Motor unit recruitment

-motor unit= 1 neuron + all muscle fibers it innervates -for a weak contraction, 2 or few motor neuron units activated -for stronger contractions, more motor neurons are recruited to contract simultaneously -# of muscle fibers/motor unit & # of motor units/muscle varies ex: hand muscles have few fibers/motor unit for precise movements and leg muscles have many fibers/motor unit for powerful movements

multiunit smooth muscle

-multiple discreet units that function independently and must be separately stimulated by autonomic nerves (neurogenic) -located in blood vessels, bronchioles, ciliary muscle, iris

skeletal muscle cells

-muscle fibers -cylindrical and lie parallel -extends entire length of muscle (tendon-fiber-tendon) - 10-100 nm diameter, up to .75 m long -derived from fusion of many myoblasts -contain multiple nuclei

Single unit smooth muscle

-muscle fibers contract as a unit and are self excitable (myogenic) -linked by gap junctions to spread potential -located in digestive system, reproductive and urinary tracts

microscopic structure of skeletal muscle cells

-myofibrils= rods within cell, 80% of cytoplasm -thick filaments= myosin proteins -thin filaments= actin proteins -arrangement of filaments= sacromeres

Ca2+ activating cross bridges in smooth muscle

-no t-tubule network -localized to just around plasma membrane -Ca2+ channels open when membrane depolarizes -Ca2+ from extraceullular fluid comes in and binds to calmodulin which activates the enzyme myosin light chain kinase, which sticks phosphates on myosin light chain necklace which activates myosin proteins to go bind to thin filaments

Starlings law of the heart

-normal hearts pump out whatever is put into it -if we increase blood filling before muscle contraction it results in a higher EDV b/c muscle fibers stretch closer to optimal length - increased VR->increased filling->increased EDV -> increased SV

Skeletal muscle relaxation

-occurs when Ca2+ is returned to lateral sac of SR when electrical stimulation stops -Ca2+ ATPase actively pumps Ca2+ from cytosol -> lateral sacs -Tropomyosin slips back to blocking myosin binding on actin -Thin filaments passively return to resting position

Spread of cardiac excitation

-originates at SA node -AP spreads throughout R&L atria via internodal pathways which causes the atria to contract -impulse reaches and passes thru AV node (AV node delay= .1 sec to ensure atria contracts before ventricles -Impulse travels down septum via bundle of his and disperses impulse throughout myocardium via purkinje fibers

reffered pain

-pain felt in a part of the body other than its actual source -each spinal nerve carries sensory info from a specific region of the body and the same spinal nerve may also supply internal organs

Semilunar valves

-positioned at junctions where major arteries leave ventricles -prevent backflow of blood from arteries into ventricles after ventricular emptying -R= pulmonary valve -L= aortic valve

Power stroke of the sliding filament theory

-power stroke= pivoting of myosin head which pulls the thin filament towards the center of the sarcomere (repeated cycles complete shortening) -cross bridges do not all pull in unison

atrioventicular valves

-prevents backflow of blood from ventricles into atria during ventricular emptying -right valve=tricupsid -left valve=mitral

Actin (thin filament) (1)

-primary component -spherical in shape, form strands, 2 strands twist together to form a helix -contains myosin binding site for myosin head to form crossbridge which forms a line called the "binding groove"

2 circulatory pathways

-pulmonary= heart, lungs, heart (closed loop of vessels) -systemic= heart, upper/lower body tissues, heart

functions of parasympathetic NS

-quiet and relaxed, "rest and digest" situations -promotes body maintenance activities (like digestion)

phasic receptors

-rapidly adapt -reduced # of AP in response to maintained stimulus -off response when stimulus removed

electrocardiogram

-records overall spread of electrical current throughout the heart -doesn't look at a single AP, looks at all AP's as they spread -not a recording of muscle contraction tension -shape of curve depends on placement of electrodes on body

Clinical correlation: Parkinson's disease

-related to destruction of basal nuclei that release dopamine -increased rigidity, unwanted tremors, slowness, loss of muscle inhibition -treatment: L-DOPA, synthetic precursor of dopamine that can cross BBB

Extrinsic control of stroke volume

-results from sympathetic NS b/c it can directly stimulate contractile cells -NE and Epi increases Ca2+ to contractile cells -> greater cross bridging -> increased force of contraction -Increases venous return by constricting veins b/c it squeezes more blood forward

sensory layer of eye

-retina= neural tissue layer containing photoreceptors

rods

-rhodopsin photopigment -mostly active in dark bc it can pick up all light -can't discriminate btwn dif wavelengths (grey shades) -low visual acuity -more numerous in periphery

Fibrous layer of eye

-sclera=white part of eye (black 5/6) -cornea=transparent anterior (1/6)

somatic afferent

-sensations arising from the body surface (pain, touch, temp) & proprioception (perception of body in space) -special senses: sight, taste, smell, hearing

smooth muscle cells

-spindle shaped -single, centrally located nucleus -do not extend the length of the muscle

Rigor mortis

-stiffening of body after death -Ca2+ leaks out of SR and still binds to form crossbridge but without a fresh ATP crossbridge dissociation isn't possible -Stiffness subsides after days due to decomposition of muscle proteins

categories of muscle

-striated= alternating dark/light bands under microscope (skeletal+cardiac) -unstriated= has no bands (smooth) -voluntary= we have control over, Somatic NS (skeletal) -involuntary= no control over, autonomic NS (cardiac+smooth)

visceral afferent

-subconscious -sensory from organs to the brain -incoming pathway for info from organs

Functions of CNS

-subconsciously regulate internal environment -voluntarily control movement -conscious awareness of body and surroundings -experience emotions -engage in higher cognitive processes (thought/memory)

ANS control of HR: sympathetic stimulation

-supplies SA node, AV nodes, conduction pathways, and contractile cells -NE released from sympathetic nerves, increases permeability to K+ and Ca2+, depolarization of cardiac nodes (reach threshold sooner, increases HR)

process of accommodation

-suspensory ligaments relax and pull the lens flatter to bend less light for distant viewing OR -suspensory ligaments contract and slack which makes lens rounder for more bending of light for nearer viewing

Sliding filament theory

-thin filaments slide inward over stationary thick filament (it overlaps to bring 2 muscle ends closer together) -the sarcomere shortens, pulls Z lines closer together, I band narrows (light strands), A band is unchanged (dark strands)

ANS control of HR: Parasympathetic stimulation

-vagus nerve contains SA node and V nodes -ACh released onto SA nodes, cells become more permeable to K+ and less to Ca2+, hyperpolarizes cardiac nodes which makes next electrical current later (lowers HR)

Semilunar valve function

-ventricles ejecting= valves open -blood falling downwards= valves closed -pocket valve= catches blood falling downward and extend into the center of the ventricle to close it off

Cardiac output (CO)

-volume of blood ejected from each ventricle every minute =HRxStroke volume (avg=5 L/min @ rest) -output of right ventricle=output of left ventricle

Venous return (VR)

-volume of blood returned to the right atrium -over time, CO=VR

4 types of gilal cells

1) Astrocytes 2)Oligodendrocytes-form mylein sheaths around axons in CNS 3)Microglia-phagocytize microorganisms&dead neurons 4)Ependymal cells-line the 4 fluid filled cavities of the brain and central cavity of spinal cord

Brain lobes

1) Frontal lobe=voluntary motor activity, speech formation, elaborating thoughts 2)Parietal lobe= receive&process sensory input (afferent neurons) 3)Temporal lobe=Auditory info, speech understanding 4)Occipital lobe=Process visual info

3 components of thin filament

1) actin 2) tropomyosin 3) troponin

ATP role in power stroke

1) attachment of cross bridge to thin filament requires the hydrolysis of ATP -> ADP 2) Movement of cross-bridge (powerstroke) released ADP from the myosin binding site 3) Detachment of the cross bridge from the thin filament requires the attachment of a fresh ATP 4)Energizing the crossbridge to repeat the cycle requires hydrolysis of fresh ATP -> ADP

ATP sources for muscle metabolism

1) creatine phosphate -can donate a P to ADP to create ATP + creatine - rested muscle has 5x as much CP than ATP - 1st energy source tapped @ onset of contractile activity 2) oxidative phosphorylation -takes place in muscle mitochondria (if O2 is present) -myoglobin= increase rate of transfer of O2 from blood to muscle -slow due to # of enzymatic steps -activity supported= aerobic/endurance type exercise 3) Glycolosis -occurs when no O2 is present in muscle b/c oxidative phosphorylation can't keep up -inefficient b/c only 2 molecules of ATP produced -2 molecules of pyruvate are converted to lactate which is responsible for burning during exercise -activity supported= anaerobic, short bursts, HIIT

Contractile cell AP

1) depolarization phase= very quick, Na+ in thru VG channels 2) very small and short repolarization= K+ out thru T-type channels 3) Ca2+ in thru L-type channels, remains depolarized 4) K+ out thru VG channels= repolarization 5) Tons of K+ out thru leaky channels (reaches resting potential of -90mV, almost freely permeable)

3 components of circulartory/cardiovascular system

1) heart=pump that establishes pressure gradient 2)blood vessels=passageway distributes blood to tissues 3)blood=transport medium

2 things that control stroke volume

1) intristic control= if we can fill ventricle with more blood, it will contract with more force. depends on EDV and length-tension relationship 2) extrinsic control= related to extent of sympathetic stimulation (tells muscle to contract w/ more force)

Ways to increase force of contraction to be useful

1) motor unit recruitment 2) Twitch summation 3) Optimal resting muscle length

All innervation by ANS is brought on by 2 neuron chains

1) preganglionic fiber: from CNS to cell body of 2nd (postganglionic neuron) 2) postganglionic fiber: from preganaglionic cell to effector organ

Functions of muscle

1) purposeful movement 2) manipulation of external objects 3) propulsion of contents through hollow organs 4) emptying contents of certain organs into external envt

reflex arc components

1)sensory receptor (respons to stimulus, muscle spindle) 2)afferent neuron (relay impulse to spinal cord) 3)integration center (input and decision) 4)efferent neuron (replay impulse back out) 5)effector (carries out response to organ)

autorhythmic cells AP

3 ions responsible = Na+, Ca2+, & K+ in 4 channels 1) repolarization= K+ leaving VG channels 2)immediate depolarization= Na+ VG channels open when cells get more - (funny channels), but not enough to get to threshold 3) Ca2+ in T-type channels=threshold 4) Ca2+ in L-type channels= spike in depolarization 5) K+ out through VG channels=repolarization CYCLE CONTINUTES b/c "funny channels" don't allow cell to rest (so heart doesn't pause)

Motor end plate does not have a threshold, so

AP's can't be initiated

PR segment of EKG

AV node delay (.2 sec) and atrial contraction

Parasympathetic receptors

Ach is released from both neurons in the circut, the preganglionic fiber releases Ach which binds to a nic cell and the postganglionic cell releases Ach which binds to muscararinic receptors

How does the neuromuscular junction function?

Ach is released from terminal axon once Ca+ enters which signals Ach to bind to nic receptor on motor end plate which opens Na+ channels which depolarizes the motor end plate and the muscle cell

In the neuromuscular junction there is no threshold along the region of the muscle, instead it is found in the

adjacent region

the PNS (peripheral nervous system) is composed of

afferent and efferent nerve fibers that relay signals between the CNS and other parts of the body

presbyopia

age related reduction in accommodation ability

isovolumetric contraction

all 4 valves are closed during contraction to generate enough pressure to open aortic valve

isovolumetric relaxation

all 4 valves closed during relaxation, dropped pressure in pulmonary and aortic valves but the pressure in the ventricle hasn't fallen enough to where tricuspid and mitral valves open

Laminar flow

all layers of blood are sliding smoothly over eachother, blood in center of vessel is flowing fastest, no sounds=normal heart function

any neuron from the CNS released to the periphery

always releases Ach which always binds to a nic receptor

The lens divides the eye into

anterior and posterior cavities

P-Wave of EKG

atrial depolarization

Heart rate is determined by

autonomic influences on SA node by cardiovascular control center of brain stem

Wiggers Diagram

a helpful study tool for students working to understand the specific coordination and timing of electrical activity (ECG), mechanical contraction, heart sounds, blood movement, and pressure change events occurring in the heart with each cardiac cycle

light rays striking a biconvex lens are refracted to a point

behind the lens (focal point)

refraction

bending light rays as they enter a transparent substance of a dif density

cholinergic receptors

bind ACh

adrenergic receptors

bind to epinephrine (epi) and norepinephrine (NE)

short waves

blue and violet

Central nervous system

brain and spinal cord

Ca2+ binding protein in smooth muscle

calmodulin

Intristic control of stroke volume

cardiac myocytes stretch when there is more blood and increase the force of contraction because heart muscle doesn't rest at optimal length

Efferent division of PNS

carries motor commands from the CNS to muscles, glands, and tissue

Afferent division of PNS

carries sensory information from PNS sensory receptors to CNS

arterties

carry blood away from ventricles

Efferent neurons

carry info from CNS to effector organs

photoreceptors

contains photo pigments that undergo chemical reactions (rods and cones)

systole

contraction of the heart and emptying of the ventricles

Cardiac cycle

contraction, relaxation, and corresponding blood flow changes

convex structures

converge light rays onto one single point

Phototransduction

converting light stimuli into electrical signals

the refractive ability of the _______ remains constant since the curvature never changes

cornea

the______ and the ______ work in conjunction to ensure focal point falls directly on retina

cornea, lens

muscle atrophy

decrease in muscle mass when muscle not used

Intensity (loudness)

depends on amplitude of wave

cells innervated by ANS have

different receptor types for different neurotransmitters and respond differently

concave structures

diverge light rays

Central sulcus

divides frontal lobe from parietal lobe

septum

divides internal heart into R/L halves to prevent the mixing of blood

type of cardiac muscle cells: autorhythmic cells

do not contract, initiate and conduct AP's to other cardiac cells, do not have a resting membrane potential (constantly polarizing or depolarizing), pacemaker potential=membrane potential slowly depolarizes until threshold is reached and -> AP

receptive fields

each somatosensory neuron responds to stimulus info within a specific region of the skin

order of the heartbeat

heart is relaxed, blood pulled into ventricles (gravity), top of heart (atria) squeezes then relaxes and the ventricles squeeze which closes blood off to the atria until it builds pressure and pops open the semilunar valves. blood is then ejected into large vesicles and AV valves still closed to prevent backflow, ventricles start to relax and pressure drops and closes semilunar valves

ventricular tachycardia

heart rate > 100 bpm, no time to fill with blood so its pumping only a fraction of what it should be

Inner ear

houses 2 different sensory systems -cochela: spiral shaped, transduces sound waves to electrical impulses for brain to understand= hearing -vestibular apparatus: balance (semicircular canals, utricle, saccule)

retinal processing in light

impulses get sent to ganglion cell then to the brain

The afferent division sends info from the

internal/external to the CNS

atrial fibrillation

irregular depolarizations of atria, no organized p-wave, "quivering", risk for stroke due to potential clotting

rods= 1 protein, rhodopsin which

is sensitive to all wavelengths of visible light

color blindness

lack of a particular cone type, most common= red-green on X chromosome in men

Brocas area

left frontal lobe, governs speaking ability

Wernickes area

left parietal/temporal/occipital lobe junction, forms coherent patterns of speech

accommodation

lens curvature is increased to view nearer objects

process of phototransduction

light, nerve fibers, ganglion cells, amacrine cells, bipolar cells, horizontal cells, rods and cones

the dorsal and ventral roots join to form a

mixed spinal nerve

Functions of ANS

most visceral organs are innervated by both sympathetic and parasympathetic and produce opposite effects in a particular organs (precise control for homeostasis)

near point

nearest point to eye at which an object can be brought into focus

Actin and myosin are sometimes called contractile proteins but...

neither of them actually contract, they just increase the overlap which shortens the sarcomere

100,000,000,000

neurons in the CNS which are all present at birth, just not connected

light is made up of

packets of energy called photos that travel in waves

the basilar membrane vibrates at the same frequency as sound that creates waves in the

perilymph

retinal processing in the dark

photoreceptor depolarized -> inhibitory synapse releases inhibitory transmitter and shuts off info to brain -> bipolar cell -> excitatory synapse -> ganglion cell (has no info to send to brain)

outer ear consists of

pinna and external auditory canal

Sympathetic receptors

preganglionic releases Ach which binds to a nic receptor on the postganglionic fiber which releases Epi/NE which bind to A, B1, or B2 receptors

each region of the basilar membrane is neurally linked to a specific region in the

primary auditory cortex in the temporal lobe

Atrial flutter

rapid and regular atrial depolarization, AV nodes prolong refractory period and prevents propagation of every AP to ventricles

Intristic heart rate

rate that would be establishes without any control from any other body part (around 100 bpm)

color vision depends on

ratios of response of the 3 cone types

long waves

red-orange

diastole

relaxation of the heart and filling of the ventricles passively

Conversion fo stimulus energy into receptor potential

sensory transduction

larger stimulus area= more likely multiple afferent neurons are stimulated

spatial summation

EKG's measure

specific cardiac events

tetany

sustained maximal contraction

larger stimulus magnitude -> larger receptor potential -> greater frequency of AP generated in afferent neuron

temporal summation

Size of receptive field depends on

the density of receptors in that region of skin

soundwaves

traveling vibrations in air due to differing densities of air molecules

ST segment of EKG

ventricular contraction

QRS complex of EKG

ventricular depolarization and atrial repolarization

T-wave of EKG

ventricular diastole/repolarization

TP interval of EKG

ventricular filling, heart at rest

end diastolic volume

volume of blood in each ventricle after filling

end systolic volume

volume of blood left in ventricle after systole

stroke volume

volume of blood pumped out of ventricle with each contraction

adequate stimulus

the specific stimulus or modality that a receptor is specialized to respond to

Arrangement of filaments in smooth muscle

-Contractile filaments oriented in diagonal diamond shape, rather than parallel -Sliding of thin filaments causes cell to shorten and balloon between thin filaments (bulging from net like structure)

Astrocytes

-Most abundant glial cell -Radiating arms hold neurons -Help maintain K+ concentration outside the cell

Autonomic NS controls heart rates and strengths of contractions

-Parasympathetic NS decreases HR and is dominant at rest -Sympathetic NS increases HR

Right and left halves of the heart are separate pumps

-R= pulmonary circulation -L= systemic circulation

hair cells in ear

-depolarize when bent in one direction which opens K+ channels -hyperpolarize when bent in other direction -inner hair cells innervated by afferent/sensory neuron -outer hair cells innervated by efferent/motor and can adjust position of tectorial membrane to help amplify sound detected by inner hair cells

optimal resting muscle length

-each muscle has an optimal length -when stimulated, muscle will relax w/ most force (overlap btwn actin and myosin provide max # cross bridges) -beginning at optimal length, max force @ tetany and beginning anywhere else, less than max force @ tetany

functions of sympathetic NS

-emergency/stressful "fight or flight" situations -prepares body for physical activity

dorsal root

-entryway for sensory fibers -afferent fibers entering dorsal root house nuclei in dorsal root ganglia

locations of autorhythmic cells

-SA node (upper R corner of R atrium=pacemaker) -AV node (base of R atrium near septum) -Bundle of His/AV Bundle (cells originate at AV node and enter septum, divides into R/L bundle branches) -Purkinje fibers (Terminal fibers that extend from bundle of his and spread throughout ventricular walls)

muscle twitch

-a brief, weak muscle contraction -result of a single AP from a single motor neuron -too short and weak to be useful

Circular muscle of iris

-active in bright light -narrows (constricts) pupil -parasympathetic NS

Tonic receptors

-adapt slowly or not at all -continue to generate AP in response to maintained stimulus -remain depolarized for as long as stimulus is turned on

middle ear

-air filled space within the temporal lobes -connected to inner ear via ossicles (malleus, incus, stapes) -Eustachian tube links middle ear to pharynx

basal nuclei (ganglia)

-area of gray matter in brain -modifies ongoing activity in motor pathways -selects and maintains purposeful motor activity and filters out unwanted movements before sent to brain stem and muscle fiber -coordinates smooth muscle activity (w thalmus)

2 divisions of efferent division of peripheral nervous system

-autonomic NS: involuntary control (cardiac and smooth muscle, exocrine glands, some endocrine glands_ -somatic NS: voluntary control (innervates skeletal muscle)

Spinal cord

-begins inferior to brain stem&spinal cord -spinal nerves (31) pair emerge from spinal cord through spaces formed btwn arches of adjacent vertebrae

Spinal nerves contain

-both sensory and motor fibers

Adrenal medulla

-center of adrenal gland -modified sympathetic ganglion that does not give rise to postganglionic fibers -stimulation of preganglionic fiber leads to secretion of Epi & NE into blood which then carries it to effector organ -NE and Epi are neurotransmitters and also catecholamine hormones

vascular layer of eye

-choroid=posterior 5/6, blood vessels -iris=colored part of eye btwn cornea and lens (contains pupil)

Cerebral cortex: frontal lobe (contains primary motor cortex)

-confers voluntary movement over skeletal muscle -controls muscles on contralateral side of body -associated w/ elaboration of thought -also associated with speech production -involves expression and comprehension - always left hemisphere (Broca's and Wernickes)

Somatic Motor Nervous System

-consists of axon of motor neurons that orginiate from ventral horn of spinal cord and innervate skeletal muscle -single neuron, axon is continuous out to effector organ -binding of Ach from neuromuscular junction to nic receptor initiates muscle contraction

cardiac muscle fibers

-cylindrical shape -striated

autonomic nerve pathways have ___ synapses to cross

2

refractive power=

1/focal distance

humans are most sensitive to sounds between

1000-4000 Hz bc the vibrations are much closer to the base

Excitation-contraction coupling in contractile cells

2 sources of cytosolic Ca2+ 1) extracellular fluid via opening of L-type channels during AP (10%), prolongs AP and contributes to beginning of muscle contraction cascade 2) This triggers Ca2+ induced Ca2+ release from SR (90%), releases tons of Ca2+ from SR which binds to troponin and leads to cross-bridging (positive feedback)

Muscle accounts for about __% of body weight in men and __% of body weight in women

40, 30 (different due to testosterone)

Light capable of being detected by photoreceptors is

400-700 nm

type of cardiac muscle cell: contractile cells

99% of cardiac muscle, do mechanical work of pumping, fire AP's but don't generate their own (they get instructions from autorhythmic cells)

Since fibers cross sides, damage to one side of auditory cortex

DOES NOT affect hearing in either ear

stimulation of receptors cause openings of nonspecific cation channels

Na+ enters cell to produce receptor potential (magnitude of potential depends on strength of stimulus)

The right ventricle is

O2 poor, low pressure+ resistance b/c it works less than the left

Stroke volume equation

SV = EDV - ESV

Stimulus for hearing

changes in pressure

AV valve function. When the heart ejects the AV valves are

closed

types of adrenergic receptors: alpha receptors

found mainly in blood vessels, take blood directly to organ, bring about excitatory response in arterioles and contracts smooth muscle, reduces blood flow to unnecessary places in fight or flight

pinna

funnels sound into external auditory canal

Sensory stimuli bring about

graded potentials (receptor potentials)

veins

return blood to the atria

4 chambers of the heart

right atrium, right ventricle, left atrium, left ventricle

somatosensory cortex

right behind central sulcus, interprets conscious awareness (pain, feeling, etc.)

Primary motor cortex

right in front of central sulcus, controls all voluntary movement

Basic unit of the myofibril

sarcomere

Types of muscle

skeletal, cardiac, smooth

Heart murmurs are caused by

turbulent blood flow 1) Stenotic valve= narrowed valve, doesn't open completely, ejecting blood makes a "whirring" sound 2)Regurgitant valve= doesn't close completely, blood leaking through an unsealed valve into the ventricle it came from, gurgling sound

transmission of soundwaves

tympanic membrane vibrates, middle ear transfers vibrations thru ossicles to oval window, waves in cochlear fluid set basilar membrane in motion, hair cells bend which transduces neural signals that are transmitted to the auditory cortex

ventricular fibrillation

uncoordinated ventricular contractions, HR=0, has to be shocked to serve as a reset for the heart